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NASA has announced plans for a massive rocket based on recycled space shuttle technology, intended to launch manned missions beyond Earth orbit in decades to come.

The Space Launch System (SLS) will make use of a central first stage equipped with no less than five shuttle main engines (the now-retired orbiter spaceplanes mounted only three) flanked by strap-on solid boosters of the same kind which used to be attached to the shuttle's disposable fuel tank. These might be replaced in time by liquid-fuelled models. Rather than bringing the central engines back for re-use, however, the SLS will discard them every time it is launched.

If at first you can't afford it ...

A similarly disposable and likewise liquid-fuelled upper stage will employ J-2X engines derived from the Apollo programme which sent men to the Moon in the 1960s and 70s. NASA thinks that the first SLS test flight might come as early as 2017, and that an initial ability to hoist 70 tonnes into orbit could be gradually increased to 130 tonnes, somewhat more than the mighty Saturn Vs of yesteryear.

According to NASA:

The SLS rocket will incorporate technological investments from the Space Shuttle Program and the Constellation Program in order to take advantage of proven hardware and cutting-edge tooling and manufacturing technology that will significantly reduce development and operations costs. It will use a liquid hydrogen and liquid oxygen propulsion system ...

This specific architecture was selected, largely because it utilizes an evolvable development approach, which allows NASA to address high-cost development activities early on in the program and take advantage of higher buying power before inflation erodes the available funding of a fixed budget. This architecture also enables NASA to leverage existing capabilities and lower development costs by using liquid hydrogen and liquid oxygen for both the core and upper stages.

It won't have escaped space-savvy readers that SLS bears a strong resemblance to the Ares V heavy lifters planned under the now defunct Constellation plans. These were axed by the incoming Obama administration after Congress refused to provide enough cash, though the Orion deep-space craft remained for no very obvious reason. On the face of it, it's hard to see why NASA thinks it can now afford to build SLS.

"We have been driving down the costs on the Space Launch System and Orion contracts by adopting new ways of doing business and project hundreds of millions of dollars of savings each year," contends NASA Deputy Administrator Lori Garver.

"This launch system will create good-paying American jobs, ensure continued US leadership in space, and inspire millions around the world," says NASA head Charles Bolden. "President Obama challenged us to be bold and dream big, and that's exactly what we are doing at NASA."

In fact President Obama stated last year that the choice of a new heavy lifter would be made in 2015, and that he wanted something new, not recycled shuttle/Apollo kit:

In developing this new vehicle, we will not only look at revising or modifying older models; we want to look at new designs, new materials, new technologies that will transform not just where we can go but what we can do when we get there.

At the time it was obvious that NASA and the established US rocket industry were upset and worried by Obama's decision to push back the decision on the heavy lifter, and to open up the task of carrying crews and supplies to the International Space Station to new players.

In particular it was obvious that Obama had been chatting to famous techbiz visionary Elon Musk, founder of upstart rocket firm SpaceX. In just eight years SpaceX has come from nowhere to successfully test-fly a rocket and capsule (Falcon 9 and Dragon) which seem quite capable of carrying astronauts into orbit. Musk has also said he will fly a Falcon-9 derived falcon Heavy in 2014 which will be the most powerful rocket then in existence, able to haul 54 tonnes to orbit.

That's not in the 70-130 tonne class required for deep space missions. But it's also well known that Musk has engineers working on new Merlin 2 engines. Rockets based on these could easily match - or beat - the planned SLS for lift: and based on a comparison between current SpaceX prices and those of the existing US rocket biz, they would be enormously cheaper. This would be partly because they use much more modern technology (being all-new designs), partly because they use cheap and easy-to-handle kerosene fuel instead of cryogenic hydrogen, and partly because SpaceX is not burdened with the huge workforces and costs of the sprawling established rocket base (the fledgling firm has only recently passed 1,000 employees).

Provided Musk can actually do what he says - reliably deliver cargoes and then crews to the ISS, and fly the biggest rocket in the USA by 2014, all at very low cost - in 2015 it would seem a no-brainer to cancel the almost certainly still-cripplingly-expensive SLS and instead order Merlin-2 based superlifters from Musk.

But that won't seem like a good idea to huge numbers of employees at NASA, Lockheed and Boeing who would build and fuel up and operate the SLS as they have the Shuttle and other existing lifters for decades. Thus it won't and doesn't seem like a good idea to many Washington politicians, who have been instrumental in assembling the SLS proposals and in the insistence that somehow NASA can afford SLS when it couldn't afford Ares V.

With that sort of political clout behind it, and with no certainty that Obama will even be in the White House come 2015, there has to be a chance that the SLS does indeed represent the future of US manned spaceflight: thus, the foreseeable future of manned flight beyond Earth orbit.

Given the past history of the Shuttle and Apollo before it, those who want to see human beings fly further, sooner and more often might easily find that a depressing prospect. ®